The major aim of this proposal is to generate new human myeloma cell lines suitable for somatic cell hybridization studies to produce human monoclonal antibodies. Because of the current lack of suitable myeloma fusion partners, the generation of human monoclonal antibodies has been limited despite the efforts of a number of innovative techniques. In order to expand the number of available myeloma cell lines from cryopreserved biopsy specimens, two novel approaches are proposed, both of which attempt to alter the malignant phenotype of thse tumors. The first approach is to gently mutagenize biopsy cells with ethyl methane sulfonate, methylnitrosourea, and CR-191. The second is to perform DNA transfection techniques with high molecular weight DNA from pre-existing myeloma and human B lymphoma cell lines and with selected hematopoietic-associated oncogenes. Initial cell culture experiments and heterotransplantation studies in the central nervous system of the nude mouse have shown that unlike the human malignant lymphomas, myelomas appear to lack some of the attributes of cell transformation. These investigations are therefore proposed to render leukemia biopsy cells more autonomous in nature and thereby capable of sustained growth in cell culture. Newly established myeloma cell lines will be extensively characterized for cytogenetic abnormalities, intracranial heterotransplantation in the nude mouse, morphology, phenotype, immunoglobulin production and gene rearrangements, and oncogene expression. After isolating HGPRT negative subclones, the myeloma cell lines will be studied in a preliminary manner for their suitability as fusion partners for the production of human monoclonal antibodies. The availability of new myeloma cell lines would greatly facilitate human hybridoma technology which is required for the generation of potential therapeutic reagents. (2)